The present invention relates to tube repair, and more particularly to securing a plug or bypass member within a tube.
Nuclear power stream supply systems, particularly the pressurized water type, include a large steam generator heat exchanger having tube and shell sides separated by a thick tube sheet. It sometimes is necessary to reduce leakage from the tube to shell sides in order to reduce the level of radioactivity ultimately released to the environment. Repairing the tube leaks is a complex undertaking because the steam generator, even when drained, is radioactive in the area of the tube sheet. Accordingly, such repair operations must be performed very quickly by hand, or be adapted for remote, automated installation.
A variety of prior tube repair techniques have been tried, but have not proven satisfactory. It has been difficult to combine the desirable attributes of quick installation, leaktight sealing throughout a wide range of thermal and stress cycling, and easy removal if later desired.